Method of making nitrogen compounds.



A. R. FRANK. METHOD OF MAKING NITROGEN COMPOUNDS.

APPLICATION FII JED JUNBfl. 1910.

Patented June 20, 1911.

-by any convenient form of igniter which %TATE T @hlt l ALBERT R. FRANK, OF HALENSEE, NEAR BERLIN, GERM:ANY, ASSIGNOR TO SOCIETA GENERALE PER LA CIANAMIDE, OF ROME, ITALY, A CORPORATION OF ITALY.

METHOD OF MAKING NITROGEN COMPOUNDS.

Original application filed March 13, 1907, Serial No.

1910. Serial T 0 all whom it may concern:

Be it known that I, ALBERT R. FRANK, a subject of His Majesty the German Emperor, residing at fl-lalensee, near Berlin. Germany, have invented certain new and useful Improvements in Methods of Producing Nit] ogen Compounds from Cal-bids; and I do hereby declare the following to be a full, clear, and exact description of the in vention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to methods of producing a nitrogen compound from carbids, and has for its object to produce such compounds, especially calcium carbid, in a manner to be more fully disclosed belowv This application is a division of my copending application Number 362, 86, entitled Method of producing nitrogen compounds from carbids, and filed March 13, 1907.

In the production of nitrogen compounds by the reaction of nitrogen with carbids, as for example, the carbide ot' the alkalis or alkaline earths, I have found that it is not necessary for the process that the entire massor" the carloid be brought to the temperature necessary for the reaction; but that is sutiices if this temperature be produced at one place in the mass, the reaction then proceeding or continuing under suitable con ditions of nitrogen supply, spontaneously throughout the entire mass; a preliminary condition, however, is that the reaction temperature be actually attained at this one place. I

In accordance with the present invention the process may be carried out in several Ways, or" .\l1lCl1 th following are eX amples:

The ignition at one place may be produced will raise the temperature at that place to the tempe ature or" the reaction, that is to say, to a temperature lying between 800" and 1100 0., Whe eupon the reaction will proceed Without the application of fiuther heat. The ignition may be accomglished, for example, by means of an electric heater or resistor in the form of a carbon body, or a metallic conductor or semiconductm placed in a heat insulated receptacle containing the carbid. The heater is then Specification of Letters Patent. Patggniged June 20, 1911 362,086. Divided and this application filed June 8,

raised to or above the reaction temperature by turning on the electric current. The nitrogen being brought into contact With the carbid in thereceptaclc the reaction starts in the heated zone and proceeds from the region of the heater until the entire mass of the carbid is converted into the desired nitrogen compound. It the heat insulation of the receptacle be suiiiciently etlective, the current may be switched oft after the reaction has commenced; but if said insulation be not sutiicicntly etl cctive, heat may be applied, through the resistor or otherwise, during the entire period of the reaction to compensate for the loss of heat.

As an illustration of one method oi": carrying out my invention, I will. select the production of calcium cyanamid (CaCN from calcium car-bid (Ca/C and'nitrogen (N),

following the reaction,

CaC +2N:CaCN +C,

which may be carried out as follows:lnto a suitable receptacle, preferably closed, constructed of material of low heat conductivity, provided with means for introducing nitrogen and containing electrical means of developing a temperature lying between dark red and light yc lO'W, I introduce the desired quantity, say 100 kg of finely divided calcium carbid. This carbid may be ground to any suitable fineness but in practice I have found it is best to grind it to such a fineness that it will, except for a residue of about 9 or 10 per cent, ai. pass through a sieve. having 900 meshes to the square (iOI'tilIHOiGI'. A small portion of the carbid immediately adjacent to the electrical heat-(leveloping i'neai'is, is first raised to the temperature required to initiate the reaction at that point between the carbid and the nitrogen then or previously introduced, and the process of conversion starts. The supply of nitrogen being maintained, the heat spontaneously resulting "rem the reuction between the llbitl and nitrogen at this initial stage which We may call the ignition stage of the process is transmitted to unis-s immediately surthat portion of the rounning the initially heated portion, and sullicicnt. to promote the fin in said surrounding portion and e develop a new supply of heat, which, transmitted to an area still more remote from the ignition pointis sutlicient to promote the reaction there; and so the reaction continues to spread until conversion of calcium carbid into calcium cyanamid is effected throughout the entire mass. This result will be recognized from the cessation in the consumption of nitrogen, which may be observed in any well known manner.

Referring to the accompanying drawings formii'lg a part of this specification in which the figure is a diz'lgrammatio sectional View of an apparatus suitable for carrying out this invention, represents any. suitable receptacle, 7) the material to be acted upon by nitrogen, c any suitable means for heating said materiahfm' example, a resistor-through which a' current may be passed; (Z the positive terminal of a work circuit; 6 the negative terminal; through which the resistor 0 may pass, 7 any suitable closure for said receptacle, and /& suitable means for introducing nitrogen gas. The method may also be carried out by bringing the carbid, reduced to a tiuely di videdv state, and either cold or moderately heated, into contact with highly heated nitrogen: under these conditions the cat-bid becomes incandescent and reacts with the nitrogen, the supply of which is amintained, the process proceeding' as before described. The nitrogen may also be supplied at a pressure above that of the atmosphere oral at mospheric pressure, or it, may be drawn into the receptacle at a pressure below that o'tv the atmosphere. In all cases the carbids may beemployed either in the pure state or as con'imereial carbids or mixed with other materials, particularly with such materials as cll'ect a loosening, ol. the carbid mass, such, for instance, as carbonaceous materials which by becoming carbonized form channels or pores in the mass, which channels or pores enable the nitrogen to penetrate readily and completely all. the portions of the mass. The carbid may be employed either in the powdered state or broken into lumps. Further, the cal-bid employed need not be completely formed carbid but maybe employed in the l'orm of its components, as, for example. a mixture of oxids, carbonates or other salts of alkalis oalkaline earths and carbon or any carljoimcemis substances;

{/ a tube or other receptacle 5 ll l l l l i l I l l l l l I l l i l l l i l it is to be clearly understood that the word carbid as used (in this specification and in the claim, signifies and includes not only all pure 'carbids as such but. also carbids' in the form of their components, such as a mixture of oxids or other salts or metals with carbonaceous material, as indicated above. The nitrogen employed may be either nitrogen as such, or nitrogen in a combined state, such, for example. as ammonia, providtal the temperature at, which the nitrogen ompound decomposes be lower than the tempcrat ure ol reaction when nitrogen acts upon carbid. it is also to be under stood that the word |1itro 'cn" as used in this specification and in the claim specifies and includes not only pn re nitrogen as such. but nitrogen mixed with small quantities of carbonic acid gas ("0 a trace of oxygen;

water vapor as well as nitrogen in the com bined state, .lior example, ammonia.

I am aware that nitrogen compounds have hitherto been produced from 'carbids by theaction of nit rogen upon carbids and 1 therefore. do not; claim such method or process broadly, but

\Vhat I claim isr The process of making compounds of nitrogen by reacting on carbids with nitrogen at a suitable tempcratlu'e, which consists in electrically dicating a relatively small part of the carbid nuiss to a reacting tei'inu-rature, supplying nitrogen as the reaction proceeds thereby maintaining the temperature and continuing the reaction thrmighout themass to be converted.

in testimony whereot, I allix my signature, in presence ot two witnesses.

Alilll l t'l It. FRANK. \Vitncsses:

lluxln' llASI'lGR, llormzatim IIAL'I'T. 

